<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <style>
        div {
            width: 100px;
            height: 100px;
            border: red 10px dotted;
            text-align: center;
        }
    </style>
</head>
<body>
    <div>zwx</div>
    <!--边框颜色：
    1.red
    2.#f00
    3.rgb(255,0,0)
    -->
    <!--边框样子
    1.solid
    2.dashed
    3.dotted
    -->
</body>
</html>